The 63-year-old has left his role as director of football at League Two Hereford to link up with Freedman, who was named the Eagles' permanent boss last week.
Co-chairman Steve Parish said: "Lennie is obviously on board because of his experience. I had a two-hour meeting with Lennie and Dougie and I was very, very impressed.
"We are really hopeful he can give Dougie a fast-track and minimise the mistakes a young manager might make."
Source: PA
Source: PA